Week 3: (In-Lab) Planning and Detailing

The primary focus this week consisted of the initial planning and detailing of the proposed walker design. First, the layout of the arm rests were sketched to decide how the sensors and physical arm rest would be placed on each side of the walker. The braking system was also considered, in terms of how the manual braking mechanism, located on each arm rest, would be connected to the spherical wheels on the front angled legs. One option, determined from the walker borrowed from Dr. Seliktar, included springs on the back two legs that stopped when pressure was applied from the arm rests, as seen in Figure 1.

Figure 1: This picture displays the spring brake attached to the wheel on the back legs of the walker.

The other option has been continuously brainstormed, consisting of a lever that is manually pressed, locking the system in place. A wire would essentially run through the piping, connecting to a rubber stopper inside of the spherical wheel casters on the front two legs. Though this idea seems complex, the idea is to safely lock the walker in place while providing comfort to the user when getting up from a seated position or while in motion. The ultimate goal of the braking and locking of the wheels consists of retaining the full range of mobility for the user. 

The wheels attached to the walker were also a concern for the proposed idea. Multiple sketches were created to determine the best and most practical type of wheel to use and connect to the angled front legs. The idea of using a 3D printer to create the caster parts was considered, but the concern of the type of material created a drawback to this idea. Other multi direction wheels were researched in lieu of finding one with an attached brake that could easily be pressed with the user's foot, as seen in Figure 2.

Figure 2: This picture displays a "Richelieu" Hardware 60 mm Silver Plate and Brake Caster found after further research. <homedepot.com> 

The brake located on the side of the wheel could be an extra locking mechanism provided for the user. The only difficulty could be attaching this type of hardware to the proposed design. However, this type of wheel helped to further develop ideas of what the existing options are already.
  

Other walkers were observed to evaluate the best hinge mechanism for the arms and foldable seat. This included the walker that was at our disposal from Dr. Selikar that had the pressure-enforced spring brakes attached to the back legs, as seen in Figure 3.

Figure 3: This figure displays the walker that was provided to us during lab from Dr. Seliktar. 

 With the use of this walker, the proper construction could be observed, which helped to raise other questions about the proposed design. This included:

• How the walker would be tested? (Non-human)
• What safety mechanism could be accounted for?
• How will the wheels lock in place from a seated position?
• How strong is the frame if enough weight is placed on it?
• How will the seat fold up and down?